Essentially a warm-up gig for the Grateful Dead’s 50th anniversary shows, this double CD documents three sets of music performed by the surviving Grateful Dead members and a crew of fellow travelers. Ostensibly a tribute to one Jerome Garcia (1942-1995), this May 2015 show in Maryland’s Merriweather Post Pavilion also celebrates the greater jam-band community, both musicians and audience, that keep the leading-averse bandleader’s increasingly codified but mostly inquisitive spirit alive.

Tribute shows, with their Teleprompter-abetted guest spots, rarely equal the real deal, and this one’s no exception. It does have its moments, however, beginning with Phil Lesh and his Communion ensemble’s show-opening “The Wheel/Uncle John’s Band,” 17 minutes so silky and sinuously tuned-in you can almost understand the bassist’s decision to blow off the rest of the event. And much of the second set stands as a kind of fathers-and-sons testament, with Dead drummer Bill Kreutzmann shepherding the Disco Biscuits and other third-generation improv-rockers through spirited renditions of Grateful Dead jam staples “Scarlet Begonias/I Know You Rider” and “Help on the Way”/”Slipknot”/”Franklin’s Tower.”

Whether joining Los Lobos for “Bertha,” or winding things down with “Touch of Grey” and “Ripple,” Bob Weir, judging by the DVD version of the show, looks vaguely uncomfortable throughout, even while performing like the wise old trooper he still is. Perhaps he’s pondering Lesh’s absence, or, even more conspicuously, that of lyricist Robert Hunter, who arguably brought as much to this music, this legacy, as did his writing partner. In any case, Weir knows there’s always another gig coming up down the road, and the final Dear Jerry letter is yet to be delivered.